Turbines include gas and steam turbines. Gas turbines include, but are not limited to, gas turbine power generation equipment and gas turbine aircraft engines. A gas turbine has a gas path which typically includes, in serial-flow relationship, an air intake (or inlet), a compressor, a combustor, a turbine, and a gas outlet (or exhaust nozzle). Gas leakage, either out of the gas path or into the gas path, from an area of higher pressure to an area of lower pressure is generally undesirable. For example, gas-path leakage in the turbine area of a gas turbine will lower the efficiency of the gas turbine leading to increased fuel costs. Also, gas-path leakage in the combustor area of a gas turbine will require an increase in burn temperature to maintain power level, such increased burn temperature leading to increased pollution, such as increased NOx and CO production.
Gas-path leakage occurs through gaps between gas turbine subassemblies such as through gaps between the combustor and the turbine, and gas-path leakage occurs through gaps between the components that make up a gas turbine subassembly, such as through gaps between combustor casing segments. Such components and subassemblies have surfaces of different shapes, suffer from assembly misalignment, and undergo vibration. Hot-section components thermally experience hot gas flow and typically undergo different thermal growths. U.S. Pat. No. 5,509,669 discloses a seal which includes a metal, ceramic, and/or polymer fiber-fabric cloth layer wrapped around a metal, ceramic, and/or polymer foil layer with the edge of the foil layer protruding beyond the foil layer and bent down to contact a gas turbine member which partially defines the leakage gap and/or with a weldment securing the seal to a gas turbine member which partially defines the leakage gap.
Steam turbines (which can be considered a special type of gas turbine) include, but are not limited to, steam turbine power generation equipment. A steam turbine includes a steam inlet, a turbine, and a steam outlet, wherein steam is the gas which turns the turbine rotor. The turbine of a steam turbine is similar to the turbine of a gas turbine and suffers from steam-path leakage the way the turbine of a gas turbine suffers from gas-path leakage.
What is needed is an improved gas-path leakage seal for a turbine which is easy to assemble and easy to install.